Fixed bug risk and antipattern using deepsource (#904)

## Description

Hi 👋 I ran the [DeepSource](https://deepsource.io/) static analyzer on the forked copy of this repo and found some [interesting code quality issues](https://deepsource.io/gh/ankitdobhal/goreplay/issues/). This PR fixes a few of them.

## Summary of Fixes

- Added .deepsource.toml to fix bug risks
- Empty string test can be improved
- Nested if can be replaced with else-if

## Type of change

- [✔] Antipattern
- [ ] New feature (non-breaking change which adds functionality)

## Checklist:

- [✔] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation

input_file.go

@@ -162,11 +162,10 @@ func (i *FileInput) init() (err error) {
 		for _, c := range resp.Contents {
 			matches = append(matches, "s3://"+bucket+"/"+(*c.Key))
 		}
-	} else {
-		if matches, err = filepath.Glob(i.path); err != nil {
+	} else if matches, err = filepath.Glob(i.path); err != nil{ 
 			Debug(0, "[INPUT-FILE] Wrong file pattern", i.path, err)
 			return
-		}
+		
 	}
 
 	if len(matches) == 0 {